Delicate articles placed in a container such as a cardboard box for shipment or storage are generally disposed within a protective cushioning material. The protective material isolates the article from large forces and shocks which may occur due to rough handling of the container. The packaging liner may take various forms.
One form of packaging liner makes use of trapped air in sealed pockets of a sheet-formed plastic material, where the pockets of trapped air are disposed intermediate the packaged article and the inner walls of the container. Commonly used "bubble pak" is one example of the use of trapped air in a packaging liner. Another example of this type of trapped-air liner is disclosed in co-pending application, Ser. No. 728,231, assigned to the assignee of the present application. In some cases, air-filled particles, or beads, may be provided within the pockets of confined air. One example of this latter approach can be found in U.S. Pat. No. 3,515,267.
Another approach for protecting sensitive, fragile articles during shipping or storage employs a foam-in-place technique wherein the outer surface of the article is covered with a surface film, followed by pouring of a liquid foam into the open container and about the article. As the foam cures, it expands, adhering to the inner surfaces of the container enclosing the packaged article and filling up the space between the article and the container. Problems have been encountered in this approach. For example, expansion of the foam about the article sometimes results in damage to the article, such as implosion of a cathode ray tube (CRT) screen, or in leakage of the foam around the film where the film does not completely cover the article. In addition, the foam adheres to the container's inner walls, precluding recycling or subsequent use of the container. This approach is also labor intensive and thus expensive and is environmentally undesirable because of the hazardous fumes emitted by the foam prior to curing. Finally, the foam is typically polyurethane which is not biodegradable and thus presents a disposal problem.
Another packaging technique involves depositing a large number of the aforementioned air-filled particles, which are commonly referred to as "peanuts" or "popcorn", into an open container housing the article to be packaged. The particles surround the article and the container is sealed. It is difficult to determine the proper number of particles for deposit in the container for optimum protection and the loose particles are difficult to handle, generally requiring a cleanup effort after the container is sealed. During handling, the particles within the container are re-distributed and tend to settle toward the bottom of the container resulting in the formation of air pockets and at least a portion of the packaged article being unprotected. In order to avoid settling, or nesting, of the loose particles, another more recent approach involves spraying a light tacky glue onto the particles as they are deposited into the container. The sprayed collection of particles forms a rigid mold about the article which is difficult to remove from the article as well as from the container because of its tackiness. If the container is shipped before the glue is allowed to cure, the particles tend to become displaced resulting in unprotected areas, or voids, around the article in the container. This approach is messy, requiring a protective layer over the packaged article, and results in the collection of particles adhering to the container's inner surface. This approach also is labor intensive.
The present invention addresses the aforementioned limitations of the prior art by providing an evacuated, encapsulating packaging liner for protecting an article within a closed container such as a cardboard box.